Mitogen-activated Protein Kinase Gene Research Articles

Frequency of MicroRNA Response Elements Identifies Pathologically Relevant Signaling Pathways in Triple-Negative Breast Cancer.

SummaryComplex interactions between mRNAs and microRNAs influence cellular functions. The mRNA-microRNA interactions also determine the post-transcriptional availability of mRNAs and unbound microRNAs. MicroRNAs binds to one or more microRNA response elements (MREs) located on the 3′UTR of mRNAs. In this study, we leveraged MREs and their frequencies in cancer and matched normal tissues to obtain insights into disease-specific interactions between mRNAs and microRNAs. We developed a bioinformatics method “ReMIx” that utilizes RNA sequencing (RNA-Seq) data to quantify MRE frequencies across the transcriptome. We applied ReMIx to triple-negative (TN) breast cancer tumor-normal adjacent pairs and identified MREs specific to TN tumors. ReMIx identified candidate mRNAs and microRNAs in the MAPK signaling cascade. Further analysis of MAPK gene regulatory networks revealed microRNA partners that influence and modulate MAPK signaling. In conclusion, we demonstrate a novel method of using MREs in the identification of functionally relevant mRNA-microRNA interactions in TN breast cancer.

Expression profiles of genes for enzymes involved in capsidiol production in Nicotiana benthamiana

In Solanaceae plants, the major phytoalexins produced during the induction of plant defense are sesquiterpenoids, such as capsidiol for Nicotiana species and rishitin for Solanum species, which are produced via the mevalonate (MVA) pathway. Eight enzymes are involved in the production of farnesyl pyrophosphate (FPP), the common precursor of phytosterols for maintaining membrane integrity and sesquiterpenoid phytoalexins for plant defense. In this study, expression profiles of N. benthamiana genes for the production of capsidiol during the induction of disease resistance were investigated. In the genome of N. benthamiana, multiple copies of genes for each enzyme in the MVA pathway were identified, and the expression of some, but not all MVA genes, was significantly upregulated after inoculation with Phytophthora infestans, or treatment with the INF1 elicitor, a secretory protein of P. infestans. For genes encoding enzymes involved in capsidiol production, 10 copies of 5-epi-aristolochene synthase (NbEAS) and six copies of 5-epi-aristolochene dihydroxylase (NbEAH) were identified, and all copies were significantly upregulated during the induction of disease resistance. Gene silencing of MAP kinase genes NbWIPK, NbSIPK, and NbNTF4 compromised INF1-induced production of phytoalexins. Expression analysis of control and NbWIPK/SIPK/NTF4-silenced plants indicated that most of the MVA genes are not under the control of these MAP kinases. In contrast, the expression pattern of NbWIPK/SIPK/NTF4 and all copies of NbEAH genes showed significant correlation, suggesting that MAP kinases are critical regulators of transcriptional upregulation of specific genes for capsidiol production.

Overexpression of Arabidopsis thaliana malonyl-CoA synthetase gene enhances cold stress tolerance by activating mitogen-activated protein kinases in plant cells

Malonyl-CoA synthetases may modulate cell responses to abiotic stress by regulating stress-related signaling transduction pathways or activating expression of transcription factors. However, the molecular mechanism of cold stress tolerance enhanced by malonyl-CoA synthetase is not fully understood. Here, we report that overexpression of the Arabidopsis thaliana malonyl-CoA synthetase gene AAE13.1 resulted in increased cell viability and growth rate and decreased thiobarbituric acid reactive substances under cold stress in rice (Oryza sativa L.), tobacco (Nicotiana tabacum), and slash pine (Pinus elliottii Engelm.). AAE13.1 was associated with cold stress tolerance by increasing the activity of ascorbate peroxidase, catalase, polyphenol oxidase, and peroxidase and the accumulation of acid phosphatase and alkaline phosphatase. Among six rice mitogen-activated protein kinase (MAPK) genes examined, AAE13.1 overexpression increased the expression of OsMAPK genes during cold stress. AAE13.1 activated expression of stress-response genes OsMAPK1, OsMAPK2, and OsMAPK3, indicating that AAE13.1 enhances cold stress tolerance by regulating expression of MAPK genes in plant cells. These results increase our understanding of cold stress tolerance in species of monocotyledons, dicotyledons, and gymnosperms.

Genome-wide identification of mitogen-activated protein kinase (MAPK) cascade and expression profiling of CmMAPKs in melon (Cucumis melo L.).

Mitogen-activated protein kinase (MAPK) is a form of serine/threonine protein kinase that activated by extracellular stimulation acting through the MAPK cascade (MAPKKK-MAPKK-MAPK). The MAPK cascade gene family, an important family of protein kinases, plays a vital role in responding to various stresses and hormone signal transduction processes in plants. In this study, we identified 14 CmMAPKs, 6 CmMAPKKs and 64 CmMAPKKKs in melon genome. Based on structural characteristics and a comparison of phylogenetic relationships of MAPK gene families from Arabidopsis, cucumber and watermelon, CmMAPKs and CmMAPKKs were categorized into 4 groups, and CmMAPKKKs were categorized into 3 groups. Furthermore, chromosome location revealed an unevenly distribution on chromosomes of MAPK cascade genes in melon, respectively. Eventually, qRT-PCR analysis showed that all 14 CmMAPKs had different expression patterns under drought, salt, salicylic acid (SA), methyl jasmonate (MeJA), red light (RL), and Podosphaera xanthii (P. xanthii) treatments. Overall, the expression levels of CmMAPK3 and CmMAPK7 under different treatments were higher than those in control. Our study provides an important basis for future functional verification of MAPK genes in regulating responses to stress and signal substance in melon.

Experience Recruits MSK1 to Expand the Dynamic Range of Synapses and Enhance Cognition.

Experience powerfully influences neuronal function and cognitive performance, but the cellular and molecular events underlying the experience-dependent enhancement of mental ability have remained elusive. In particular, the mechanisms that couple the external environment to the genomic changes underpinning this improvement are unknown. To address this, we have used male mice harboring an inactivating mutation of mitogen- and stress-activated protein kinase 1 (MSK1), a brain-derived neurotrophic factor (BDNF)-activated enzyme downstream of the mitogen-activated protein kinase (MAPK) pathway. We show that MSK1 is required for the full extent of experience-induced improvement of spatial memory, for the expansion of the dynamic range of synapses, exemplified by the enhancement of hippocampal long-term potentiation (LTP) and long-term depression (LTD), and for the regulation of the majority of genes influenced by enrichment. In addition, and unexpectedly, we show that experience is associated with an MSK1-dependent downregulation of key MAPK and plasticity-related genes, notably of EGR1/Zif268 and Arc/Arg3.1, suggesting the establishment of a novel genomic landscape adapted to experience. By coupling experience to homeostatic changes in gene expression MSK1, represents a prime mechanism through which the external environment has an enduring influence on gene expression, synaptic function, and cognition.SIGNIFICANCE STATEMENT Our everyday experiences strongly influence the structure and function of the brain. Positive experiences encourage the growth and development of the brain and support enhanced learning and memory and resistance to mood disorders such as anxiety. While this has been known for many years, how this occurs is not clear. Here, we show that many of the positive aspects of experience depend on an enzyme called mitogen- and stress-activated protein kinase 1 (MSK1). Using male mice with a mutation in MSK1, we show that MSK1 is necessary for the majority of gene expression changes associated with experience, extending the range over which the communication between neurons occurs, and for both the persistence of memory and the ability to learn new task rules.

Genome-Wide Identification, Phylogeny, and Expressional Profiles of the Mitogen-Activated Protein Kinase Kinase Kinase (MAPKKK) Gene Family in Pyropia yezoensis

Mitogen-activated protein kinase kinase kinases (MAPKKKs) are pivotal components of MAPK cascades. Pyropia yezoensis, belonging to Rhodophyta, is an important macroalga growing in the intertidal zone of temperate Japan and China. At present, little is known about MAPKKKs and their potential regulatory mechanisms in response to environmental stressors in red algae, particularly with regard to how this gene family retained its ancient characteristics. In this study, we identified 33 MAPKKK genes in P. yezoensis by bioinformatics analysis. Phylogenetic analysis classified them into Raf, MEKK and ZIK groups, which contained conserved kinase motif with minor variations. The number of intron of all PyMAPKKK is few, up to 3. Regulatory elements prediction indicated that the cis-acting elements included many motifs involved in the stress response. Furthermore, expression analysis of PyMAPKKKs under different stress conditions revealed that numerous PyMAPKKK genes were involved in various signaling pathways with different expression patterns. Additionally, 16 PyMAPKKK genes were validated their expression patterns by Realtime-PCR analysis. An interactome network of PyMAPKKK was constructed to show that most of the interacting proteins were serine/threonine protein kinases, MAPKs, and ubiquitin-binding proteins. Our study provided helpful information for understanding the evolution and function of the MAPKKK family in P. yezoensis.

Genome-wide identification of the mitogen-activated protein kinase (MAPK) family in cotton (Gossypium hirsutum) reveals GhMPK6 involved in fiber elongation.

Mitogen-activated protein kinases (MAPKs) are important in regulating plant development as well as stress response. In this study, we genome-widely identified 56 MAPK genes in upland cotton. These MAPK genes unequally distribute on 22 chromosomes of cotton genome, but no MAPK gene is located on At_Chr6, Dt_Chr6, At_Chr13 and Dt_Chr13. The exons and introns in GhMAPK gene family vary widely at the position, number and length. Furthermore, GhMAPK family can be divided into 4 groups (A, B, C and D), and the TEY type of T-loop exists in three groups (A, B and C), but the TDY type of T-loop is only in group D. Further study revealed that some GhMAPK genes (including GhMPK6) are preferentially expressed in elongating fibers. GhMPK6 maintains a high phosphorylation level in elongating fibers, and its phosphorylation was enhanced in fibers by phytohormones brassinosteroid (BR), ethylene and indole-3-acetic acid (IAA). Additionally, GhMPK6 could interact with GhMKK2-2 and GhMKK4, suggesting that GhMKK2-2/4-GhMPK6 module may be involved in phosphorylation of its downstream proteins for regulating fiber elongation of cotton.

Arbuscular mycorrhizal fungi enhanced drought resistance in apple by regulating genes in the MAPK pathway

Arbuscular mycorrhizal fungi (AMF) can form a symbiotic relationships with most terrestrial plants and play an important role in plant growth and adaptation to various stresses. To study the role of AMF in regulating drought resistance in apple, the effects of drought stress on Malus hupehensis inoculated with AMF were investigated. Inoculation of AMF enhanced apple plants growth. Mycorrhizal plants had higher total chlorophyll concentrations but lower relative electrolyte leakage under drought stress. Mycorrhizal plants increased net photosynthetic rate, stomatal conductance, and transpiration rate under drought stress, however, they showed lower inhibition in the quantum yield of PSII photochemistry. Mycorrhizal plants also had higher superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) enzyme activities under drought conditions. Thus, mycorrhizal plants had lower accumulated MDA, H2O2, and O2− than non-mycorrhizal seedlings. Total sugar and proline concentrations also significantly increased, helping maintain the osmotic balance. Furthermore, mitogen-activated protein kinase (MAPK) cascades, which participate in the regulation of responses of plants and microorganisms to biotic and abiotic stress, were up-regulated in apple plants and AMF during drought. We saw that there were at least two motifs that were identical in MAPK proteins and many elements that responded to hormones and stress from these MAPK genes. In summary, our results showed that mycorrhizal colonization enhanced apple drought tolerance by improving gas exchange capacity, increasing chlorophyll fluorescence parameters, creating a greater osmotic adjustment capacity, increasing scavenging of reactive oxygen species (ROS), and using MAPK signals for interactions between AMF and their apple plant hosts.

Molecular characterization of p38 MAPK and tissue-specific expression under cadmium stress in red swamp crayfish (Procambarus clarkii)

Keeping harmful pollutants out of some crucial tissues as much as possible is a key trait for the organism to survive in adverse conditions, such as in heavy-metal contaminated aquatic environments. In the current study, it was hypothesized that the p38 Mitogen-activated Protein Kinase (MAPK) controls the distribution of cadmium (Cd) in red swamp crayfish (Procambarus clarkii) by regulating the accumulation of Cd in different tissues under Cd-stressed conditions. To test this hypothesis, this study analyzed the p38 MAPK gene and compared the differential expression levels in the heart, antennal gland, gill, hepatopancreas, and muscles. Differences in expression levels of p38 MAPK gene between different tissues were conducted under controlled Cd exposure. This study found that the expression of p38 MAPK is tissue-specific in all tested samples under non-stressed condition. Under Cd-stressed condition and with the prolongation of Cd exposure time, the content of Cd in all examined tissues of P. clarkii has substantially increased compared to the control, although the Cd contents in the heart, antennal gland, and muscle remained relatively lower than those observed in the hepatopancreas. Consequently, the levels of p38 MAPK in the heart, antennal gland, and muscle were higher than the level in the hepatopancreas. These results indicate that p38 MAPK regulates the distribution and accumulation of Cd in different tissues of P. clarkii under Cd-stressed condition. Furthermore, the results suggested that the higher expression of p38 MAPK played a crucial role in keeping Cd out of the tissues in the Cd-rich aquatic environment to maintain the normal physiological function of the red swamp crayfish, a process necessary for survival and growth.

A strawberry mitogen-activated protein kinase gene, FaMAPK19, is involved in disease resistance against Botrytis cinerea

Mitogen-activated protein kinase (MAPK) cascades are highly conserved signaling modules involved in a wide range of resistance strategies against pathogen attack. However, the function of strawberry (Fragaria × ananassa) MAPKs in resistance against Botrytis cinerea remains unclear. The present study investigated the functional role of FaMAPK19 in the regulation of defense responses in strawberry fruit to B. cinerea. Changes in FaMAPK19 expression levels throughout whole-plant development and phenotypes of strawberry fruit after B. cinerea inoculation exhibited strong relationships with the level of FaMAPK19 transcripts and severity of gray mold. Transient transformation was carried out to overexpress FaMAPK19 and its antisense transcript in strawberry fruits, which were later analyzed upon B. cinerea inoculation. The distinct phenotypes of transformed fruits indicated that overexpression of FaMAPK19 improved disease resistance to B. cinerea, but antisense expression of FaMAPK19 caused a reduction in disease resistance. Disease resistance–related transcription factors were almost all upregulated in fruits where FaMAPK19 was overexpressed. These results suggest that FaMAPK19 plays a pivotal role in defense responses in strawberry fruit to B. cinerea. Moreover, we found that the transcript levels of some hormone-related genes, some structural genes, and a series of ripening-related genes were highly influenced by overexpression and antisense expression of FaMAPK19 in fruits, suggesting that FaMAPK19 might also have functions in fruit development and ripening. We thus hypothesize that the FaMAPK19 gene plays a key role in fruit disease resistance as well as a variety of biological functions, including fruit development and ripening regulation.

Role of the Arabidopsis calcineurin B-like protein-interacting protein kinase CIPK21 in plant cold stress tolerance

The Arabidopsis calcineurin B-like protein-interacting protein kinase CIPK21 gene (AtCIPK21) plays important roles in cell metabolism, plant development, and abiotic stress responses. However, the function of the AtCIPK21 gene in cold stress tolerance in plant cells is not fully understood. In this study, we use cell cultures of three plant species including rice (Oryza sativa L.), cotton (Gossypium hirsutum L.), and white pine (Pinus strobus L.), as well as Agrobacterium tumefaciens strain GV3101 harboring pBI-AtCIPK21 to generate transgenic cell lines. After confirmation of integration of the AtCIPK21 gene into the genome by polymerase chain reaction (PCR), southern blotting, and northern blotting analyses, the rice, cotton, and pine AtCIPK21 transgenic cell lines were used to examine cold stress tolerance. The experimental results demonstrated that overexpression of the AtCIPK21 gene enhanced cold stress tolerance of transgenic cells by increasing cell viability and cell growth rate, decreasing lipid peroxidation and ion leakage, increasing the content of polyamines, as well as elevating the activity of antioxidative enzymes. In rice cells, AtCIPK21 increases expression of Ca2+-dependent protein kinase (CPK) genes and mitogen-activated protein kinase (MAPK) genes under cold stress. These results indicated that overexpression of the AtCIPK21 gene in plant cells improved cold stress tolerance by elevating polyamines content, antioxidative enzyme activity, and expression of CPK genes and MAPK genes. Overexpression of the AtCIPK21 gene may be a valuable approach for engineering plant cold stress tolerance.

Molecular characterization and expression analysis of two crucial MAPKs- jnk1 and erk1 as cellular signal transducers in Labeo rohita in response to PAMPs stimulation and pathogenic invasion.

Mitogen-activated protein kinases (MAPKs) are crucial Ser/Thr protein kinases that play important roles in innate immunity by converting extracellular stimuli into a wide range of cellular responses, including the production of cytokines. In this study, two MAPK genes, jnk1 and erk1, were cloned and characterized in rohu (Labeo rohita), a commercially important freshwater fish species in the Indian subcontinent. In healthy rohu, both jnk1 and erk1 gene expressions were highest in the spleen as compared to gill, liver, blood and kidney tissues. In vitro stimulation of the L. rohita gill (LRG) cell line with γ-D-glutamyl-meso-diaminopimelic acid, muramyl dipeptide and polyinosinic: polycytidylic acid (poly I:C) resulted in significantly enhanced expressions of jnk1 and erk1 genes. In the in vivo experiments, jnk1 and erk1 gene expressions were also enhanced in lipopolysaccharides and poly I:C-treatment. Infection of rohu fingerlings with Aeromonas hydrophila and Bacillus subtilis revealed significantly enhanced expressions of the jnk1 and erk1 genes in all of the tested organs/tissues. Together these results imply the important role of jnk1 and erk1 genes in fish during pathogenic invasion and diseases.

Overexpression of Arabidopsis thaliana cysteine2/histidine2-type transcription factor 6 gene enhances plant resistance to a bacterial pathogen

Transcription factors can be used to engineer plants for enhanced productivity. However, the mechanism(s) by which the C2H2-type zinc finger transcription factor enhances pathogen resistance in cells is not fully understood. Here, Agrobacterium tumefaciens carrying the gene for Arabidopsis thaliana cysteine2/histidine2-type transcription factor 6 (ZAT6) was used to engineer rice (Oryza sativa L.), cotton (Gossypium hirsutum L.), and slash pine (Pinus elliottii Engelm.) to generate transgenic cell lines. Transgenic cells were then inoculated with the pathogenic bacterium Pseudomonas syringae. Compared to the control, cell viability of transgenic cells increased 39–47% and growth rate increased 9–15% by 7 days after inoculation in rice, cotton and slash pine. Acid phosphatase activity and alkaline phosphatase activity and transcript levels of Ca2+-dependent protein kinase genes OsCPK1, OsCPK2, OsCPK6, and OsCPK8 and mitogen-activated protein kinase genes OsMAPK1, OsMAPK2, OsMAPK3, and OsMAPK8 increased significantly in transgenic rice cells by 3 day after inoculation, and extracellular pH had decreased by 10–14% by 96 min after inoculation in transgenic rice, cotton and slash pine cells. These results suggest that ZAT6 enhances P. syringae resistance in plant cells by modulating transcription of CPK and MAPK and oxidase activity.

Curative Treatment of Candidiasis by the Live Biotherapeutic Microorganism Lactobacillus rhamnosus Lcr35® in the Invertebrate Model Caenorhabditis elegans: First Mechanistic Insights.

The resistance of Candida albicans to conventional drug treatments, as well as the recurrence phenomena due to dysbiosis caused by antifungal treatments, have highlighted the need to implement new therapeutic methodologies. The antifungal potential of live biotherapeutic products (LBP) has already been demonstrated using preclinical models (cell cultures, laboratory animals). Understanding their mechanisms of action is strategic for the development of new therapeutics for humans. In this study, we investigated the curative anti-C. albicans properties of Lactobacillus rhamnosus Lcr35® using the in vitro Caco-2 cell and the in vivo Caenorhabditis elegans models. We showed that Lcr35® does inhibit neither the growth (p = 0.603) nor the biofilm formation (p = 0.869) of C. albicans in vitro. Lcr35® protects the animal from the fungal infection (+225% of survival, p < 2 × 10–16) even if the yeast is detectable in its intestine. In contrast, the Lcr35® cell-free supernatant does not appear to have any antipathogenic effect. At the mechanistic level, the DAF-16/Forkhead Box O transcription factor is activated by Lcr35® and genes of the p38 MAP Kinase signaling pathway and genes involved in the antifungal response are upregulated in presence of Lcr35® after C. albicans infection. These results suggest that the LBM strain acts by stimulating its host via DAF-16 and the p38 MAPK pathway.

Alleviating effects of exogenous melatonin on salt stress in cucumber

Melatonin (N-acetyl-5-methoxytryptamine) is an important molecule in plants that regulates growth and development and responds to abiotic stresses. In this study, we studied the role of exogenous melatonin in alleviating salt stress in cucumber. The results showed that exogenous melatonin pretreatment could improve cell viability, protect photosynthesis, increase antioxidant enzyme activity, inhibit active oxygen explosion, reduce malondialdehyde (MDA) content and relative conductivity in cucumber Seedlings under salt stress compared with salt stress alone. Gene expression analysis showed that melatonin significantly increased the expression of antioxidant enzyme gene, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase genes, mitogen-activated protein kinase (MAPK) genes (MAPK3, MAPK4, MAPK6) and salt overly sensitive (SOS) genes (SOS1, SOS2, SOS3) under salt stress. diphenyleneiodonium (DPI) or dimethylthiourea (DMTU) significantly reduced melatonin-induced defense responses, including decreased antioxidant enzyme activity and photosynthesis protection, as well as the expression of stress-related genes. Similar to DPI and DMTU, U0126 (MEK inhibitor) also reduces melatonin-induced defense responses. In conclusion, our study shows that exogenous melatonin treatment can effectively alleviate the damage of salt stress on cucumber seedlings, and the alleviation effect is related to hydrogen peroxide (H2O2). And there may be interactions between melatonin-mediated salt tolerance and the MAP kinase signaling pathway.

Connection the Rhizomicrobiome and Plant MAPK Gene Expression Response to Pathogenic Fusarium oxysporum in Wild and Cultivated Soybean.

Little known the connections between soybeans mitogen-activated protein kinase (MAPK) gene expression and the rhizomicrobiome upon invasion of the root pathogen Fusarium oxysporum. To address this lack of knowledge, we assessed the rhizomicrobiome and root transcriptome sequencing of wild and cultivated soybean during the invasion of F. oxysporum. Results indicated F. oxysporum infection enriched Bradyrhizobium spp. and Glomus spp. and induced the expression of more MAPKs in the wild soybean than cultivated soybean. MAPK gene expression was positively correlated with Pseudomonadaceae but negatively correlated with Sphingomonadaceae and Glomeraceae in both cultivated and wild soybean. Specifically, correlation profiles revealed that Pseudomonadaceae was especially correlated with the induced expression of GmMAKKK13-2 (Glyma.14G195300) and GmMAPK3-2 (Glyma.12G073000) in wild and cultivated soybean during F. oxysporum invasion. Main fungal group Glomeraceae was positively correlated with GmMAPKKK14-1 (Glyma.18G060900) and negatively correlated with GmRaf6-4 (Glyma.02G215300) in the wild soybean response to pathogen infection; while there were positive correlations between Hypocreaceae and GmMAPK3-2 (Glyma.12G073000) and between Glomeraceae and GmRaf49-3 (Glyma.06G055300) in the wild soybean response, these correlations were strongly negative in the response of cultivated soybean to F. oxysporum. Taken together, MAPKs correlated with different rhizomicrobiomes indicating the host plant modulated by the host self-immune systems in response to F. oxysporum.

LncRNA ST8SIA6-AS1 promotes proliferation, migration and invasion in breast cancer through the p38 MAPK signalling pathway.

Long non-coding RNAs (lncRNAs) are regarded as important functional regulators of various biological processes and are also known to be involved in the occurrence and development of human cancers, including breast cancer (BC). In our present study, the RNA expression profiling data for a large cohort of human BC samples were obtained from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases, and the differentially expressed lncRNAs were screened out. We found that the expression of ST8SIA6-AS1 was elevated in BC tumour tissues compared with the adjacent normal tissues in the samples from the TCGA and GEO datasets, as well as in 138 BC tissue samples obtained by us. The high expression of ST8SIA6-AS1 was associated with estrogen receptor-negative, progesterone receptor-negative, advanced tumour-node-metastasis stage and worse survival in BC patients. In vitro functional studies revealed that high expression of ST8SIA6-AS1 promoted proliferation, invasion and migration of BC cell lines. The results of the in vivo studies indicated that upregulation of ST8SIA6-AS1 promoted xenograft tumour growth of BC. Mechanistically, ST8SIA6-AS1 regulated AKT1 and p38 mitogen-activated protein kinase (MAPK) gene expression by affecting their mRNA and protein levels, respectively, and it also affected the phosphorylation of AKT1 protein. Rescue experiments indicated that ST8SIA6-AS1 promoted BC cell proliferation, invasion and migration in a p38 MAPK signalling-mediated manner. Together, our data suggest that ST8SIA6-AS1 plays an important role in the occurrence and development of BC and may therefore serve as a promising therapeutic target.

BnaMPK6 is a determinant of quantitative disease resistance against Sclerotinia sclerotiorum in oilseed rape

Sclerotinia sclerotiorum causes a devastating disease in oilseed rape (Brassica napus), resulting in major economic losses. Resistance response of B. napus against S. sclerotiorum exhibits a typical quantitative disease resistance (QDR) characteristic, but the molecular determinants of this QDR are largely unknown. In this study, we isolated a B. napus mitogen-activated protein kinase gene, BnaMPK6, and found that BnaMPK6 expression is highly responsive to infection by S. sclerotiorum and treatment with salicylic acid (SA) or jasmonic acid (JA). Moreover, overexpression (OE) of BnaMPK6 significantly enhances resistance to S. sclerotiorum, whereas RNAi in BnaMPK6 significantly reduces this resistance. These results showed that BnaMPK6 plays an important role in defense to S. sclerotiorum. Furthermore, expression of defense genes associated with SA-, JA- and ethylene (ET)-mediated signaling was investigated in BnaMPK6-RNAi, WT and BnaMPK6-OE plants after S. sclerotiorum infection, and consequently, it was indicated that the activation of ET signaling by BnaMPK6 may play a role in the defense. Further, four BnaMPK6-encoding homologous loci were mapped in the B. napus genome. Using the allele analysis and expression analysis on the four loci, we demonstrated that the locus BnaA03.MPK6 makes an important contribution to QDR against S. sclerotiorum. Our data indicated that BnaMPK6 is a previously unknown determinant of QDR against S. sclerotiorum in B. napus.

MAPKKK gene family in Dunaliella salina: identification, interaction network, and expression patterns under abiotic stress

Mitogen-activated protein kinase kinase kinase (MAPKKK) is a component of the MAPK cascade pathway that plays an essential role in plant growth, development, and response to biotic and abiotic stress in several plant species. However, the MAPKKK family genes from the green alga Dunaliella salina have not been thoroughly characterized to date. In this study, we performed transcriptome and bioinformatics analyses of the MAPKKK gene family in D. salina. Thirty-three DsMAPKKK genes were identified, and 17 DsMAPKKK cloned genes which can significantly respond to salt, hyperosmotic, and oxidative stresses were considered to be the key potential genes involved in the abiotic stress mechanisms in D. salina. Phylogenetic analysis indicated that the 17 DsMAPKKKs could be classified into three subfamilies. Conserved motif analysis showed that the 17 DsMAPKKKs had typical domains and had some specific domains. Interestingly, one of the DsMAPKKK genes had both a GAF domain and a PAS domain, while no MAPKKK genes exhibited these two domains in other plant species, thereby representing a source of adaptive plasticity that is specific to D. salina. Furthermore, we used the STRING database to predict the interaction network and the DsMAPKKK9-DsMEK1, DsMAPKKK12-DsMEK2 interaction pathways were confirmed by the Y2H assay, which implies that these interaction pathways may regulate cytokinesis in D. salina. In conclusion, homologous mapping and the Y2H assay validated two MAPKKK-MAPKK cascade pathways in D. salina. These data further promote our understanding of the intricate transcriptional control of MAPKKK-MAPKK genes and provide pivotal candidate genes for the protein interaction network in D. salina.

PATH-38. ROSETTE-FORMING GLIONEURONAL TUMOR IS DEFINED BY FGFR1 ACTIVATING ALTERATIONS WITH FREQUENT ACCOMPANYING PI3K AND MAPK PATHWAY MUTATIONS

Abstract BACKGROUND Rosette-forming glioneuronal tumor (RGNT) is an uncommon CNS tumor originally described in the fourth ventricle characterized by a low-grade glial neoplasm admixed with a rosette-forming neurocytic component. METHODS We reviewed clinicopathologic features of 42 patients with RGNT. Targeted next-generation sequencing was performed, and genome-wide methylation profiling is underway. RESULTS The 20 male and 22 female patients had a mean age of 25 years (range 3–47) at time of diagnosis. Tumors were located within or adjacent to the lateral ventricle (n=16), fourth ventricle (15), third ventricle (9), and spinal cord (2). All 31 tumors assessed to date contained FGFR1 activating alterations, either in-frame gene fusion, kinase domain tandem duplication, or hotspot missense mutation in the kinase domain (p.N546 or p.K656). While 7 of these 31 tumors harbored FGFR1 alterations as the solitary pathogenic event, 24 contained additional pathogenic alterations within PI3-kinase or MAP kinase pathway genes: 5 with additional PIK3CA and NF1 mutations, 4 with PIK3CA mutation, 3 with PIK3R1 mutation (one of which also contained focal RAF1 amplification), 5 with PTPN11 mutation (one with additional PIK3R1 mutation), and 2 with NF1 deletion. The other 5 cases demonstrated anaplastic features including hypercellularity and increased mitotic activity. Among these anaplastic cases, 3 harbored inactivating ATRX mutations and two harbored CDKN2A homozygous deletion, in addition to the FGFR1 alterations plus other PI3-kinase and MAP kinase gene mutations seen in those RGNT without anaplasia. CONCLUSION Independent of ventricular location, RGNT is defined by FGFR1 activating mutations or rearrangements, which are frequently accompanied by mutations involving PIK3CA, PIK3R1, PTPN11, NF1, and KRAS. Whereas pilocytic astrocytoma and ganglioglioma are characterized by solitary activating MAP kinase pathway alterations (e.g. BRAF fusion or mutation), RGNT are genetically more complex with dual PI3K-Akt-mTOR and Ras-Raf-MAPK pathway activation. Rare anaplastic examples may show additional ATRX and/or CDKN2A inactivation.